1. Field of the Invention
The invention relates to a composite material used in industrial machinery, consumer appliances and other various fields, and particular, to a composite material having vibration-damping properties.
2. Description of the Related Art
The term “vibration-damping property” used herein is to be understood to include a vibration-damping function.
A composite material having vibration-damping properties is considered to be used in industrial machinery, consumer appliances and other various fields. Use thereof in a vehicle will be described as an example. A vehicle has a lot of vibration sources including a drive-train such as engine. Therefore, it is desirable that a composite material having vibration-damping properties be used for a vibration source or peripheral equipments to reduce generation of vibration itself or influence thereof as much as possible.
A laminated damping steel sheet is proposed as a damping material having such a vibration-damping function. The laminated damping steel sheet has a structure in which a sheet made of a resin is arranged between two steel sheets such that the resin sandwiched between the two steel sheets acts to absorb vibration. Such a technique is disclosed in JP-A-S64-014027.
Another example is a clad spring material having a three-layer structure in which copper layers are provided on both surfaces of stainless steel. The three-layer clad spring material has a non-joined portion formed at an interface between the stainless steel and the copper layer so that vibration is absorbed at the non-joined portion. Such a technique is disclosed in JP-A-H02-217184.